Delta Air Lines said on Wednesday it would make a major change to its frequent-flier program, basing the number of miles earned toward free flights on how much customers spend rather than the distance traveled.

The change, which will take effect next year, will sweeten mileage awards for travelers who pay more for airline tickets, the carrier said in a statement.

Delta said the new program would favor "frequent business travelers" and leisure fliers who buy tickets at higher fares. Generally, business passengers pay more than leisure travelers.

Passengers will garner between five and 11 miles for each dollar spent on airfares depending on their frequent-flier status under the changes, the carrier said.

"The travel industry, including nearly all hotel and credit card programs, has already moved to a spend-based model," Jeff Robertson, vice president for Delta's SkyMiles loyalty program, said in the statement. "Delta will become the first U.S. global carrier to make this transition to better reward our most loyal customers."